Hemolysis
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Hemolysis or haemolysis (Template:IPAc-en),<ref name="lpd">Template:Cite book</ref> also known by several other names, is the rupturing (lysis) of red blood cells (erythrocytes) and the release of their contents (cytoplasm) into surrounding fluid (e.g. blood plasma). Hemolysis may occur in vivo or in vitro.
One cause of hemolysis is the action of hemolysins, toxins that are produced by certain pathogenic bacteria or fungi. Another cause is intense physical exercise.<ref>Template:Cite journal</ref> Hemolysins damage the red blood cell's cytoplasmic membrane, causing lysis and eventually cell death.<ref>Template:Cite book</ref>
EtymologyEdit
From hemo- + -lysis, from Ancient Greek {{#invoke:Lang|lang}} ({{#invoke:Lang|lang}}, 'blood') + {{#invoke:Lang|lang}} {{#invoke:Lang|lang}}, 'loosening').
Inside the bodyEdit
Hemolysis inside the body can be caused by a large number of medical conditions, including some parasites (e.g., Plasmodium), some autoimmune disorders (e.g., autoimmune haemolytic anaemia, drug-induced hemolytic anemia, atypical hemolytic uremic syndrome (aHUS)<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>),<ref name=":0">Template:Cite journal</ref> some genetic disorders (e.g., Sickle-cell disease or G6PD deficiency), or blood with too low a solute concentration (hypotonic to cells).<ref name=":1">Template:Cite journal</ref>
Hemolysis can lead to hemoglobinemia due to hemoglobin released into the blood plasma, which plays a significant role in the pathogenesis of sepsis<ref name="Effenberger-Neidnicht 2018 1569–1581">Template:Cite journal</ref> and can lead to increased risk of infection due to its inhibitory effects on the innate immune system.<ref name="Effenberger-Neidnicht 2018 1569–1581"/>
Parasitic hemolysisEdit
Because the feeding process of the Plasmodium parasites damages red blood cells, malaria is sometimes called "parasitic hemolysis" in medical literature.Template:Citation needed
HELLP, pre-eclampsia, or eclampsiaEdit
- See HELLP syndrome, Pre-eclampsia, and Eclampsia
Hemolytic disease of the newbornEdit
{{#invoke:Labelled list hatnote|labelledList|Main article|Main articles|Main page|Main pages}} Hemolytic disease of the newborn is an autoimmune disease resulting from the mother's antibodies crossing the placenta to the fetus. This most often occurs when the mother has previously been exposed to blood antigens present on the fetus but foreign to her, through either a blood transfusion or a previous pregnancy.<ref>Template:Cite journal</ref>
Hemolytic anemiaEdit
{{#invoke:Labelled list hatnote|labelledList|Main article|Main articles|Main page|Main pages}} Because in vivo hemolysis destroys red blood cells, in uncontrolled, chronic or severe cases it can lead to hemolytic anemia.
Hemolytic crisisEdit
A hemolytic crisis, or hyperhemolytic crisis, is characterized by an accelerated rate of red blood cell destruction leading to anemia, jaundice, and reticulocytosis.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Hemolytic crises are a major concern with sickle-cell disease and G6PD deficiency.
Toxic agent ingestion or poisoningEdit
Paxillus involutus ingestion can cause hemolysis.
Space hemolysisEdit
Spaceflight can cause hemolysis.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
Intrinsic causesEdit
Hemolysis may result from intrinsic defects in the red blood cell itself:<ref name="Jacobasch Rapoport 1996 pp. 143–70">Template:Cite journal</ref><ref name="Bossi Russo 1996 pp. 171–88">Template:Cite journal</ref>
- Defects of red blood cell membrane production (as in hereditary spherocytosis and hereditary elliptocytosis)
- Defects in hemoglobin production (as in thalassemia, sickle-cell disease and congenital dyserythropoietic anemia)
- Defective red cell metabolism (as in glucose-6-phosphate dehydrogenase deficiency and pyruvate kinase deficiency)
- Paroxysmal nocturnal hemoglobinuria (PNH), sometimes referred to as Marchiafava-Micheli syndrome, is a rare, acquired, potentially life-threatening disease of the blood characterized by complement-induced intravascular hemolytic anemia.
Extrinsic causesEdit
Extrinsic hemolysis is caused by the red blood cell's environment:<ref name=":0" /><ref name=":1" />
- Immune-mediated causes could include transient factors as in Mycoplasma pneumoniae infection (cold agglutinin disease) or permanent factors as in autoimmune diseases like autoimmune hemolytic anemia<ref name=":0" /> (itself more common in diseases such as systemic lupus erythematosus, rheumatoid arthritis, Hodgkin's lymphoma, and chronic lymphocytic leukemia).
- Spur cell hemolytic anemia
- Any of the causes of hypersplenism (increased activity of the spleen), such as portal hypertension.
- Acquired hemolytic anemia is also encountered in burns and as a result of certain infections (e.g. malaria).
- Lead poisoning or poisoning by arsine or stibine causes non-immune hemolytic anemia.<ref name=":1" />
- Runners can develop hemolytic anemia due to "footstrike hemolysis", the destruction of red blood cells in feet at foot impact.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>
- Low-grade hemolytic anemia occurs in 70% of prosthetic heart valve recipients, and severe hemolytic anemia occurs in 3%.<ref>Template:Cite bookTemplate:Dead link</ref>
Intravascular hemolysisEdit
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Intravascular hemolysis describes hemolysis that happens mainly inside the vasculature.<ref name="Stanley 2018">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> As a result, the contents of the red blood cell are released into the general circulation, leading to hemoglobinemia<ref name="eClinpath Intravascular hemolysis">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> and increasing the risk of ensuing hyperbilirubinemia.<ref name="Muller Jacobsen Healy McMickan 2006 pp. 229–241">Template:Cite journal</ref>
Intravascular hemolysis may occur when red blood cells are targeted by autoantibodies, leading to complement fixation, or by damage by parasites such as Babesia.<ref name="eClinpath Bilirubin and hemolytic anemia">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Additionally, thrombotic microangiopathy (TMA) can result in hemolysis of red blood cells.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> TMA is frequently observed in aHUS patients where clots form in the small vessels of the kidney resulting in damaged red blood cells as they attempt to pass through the restricted vessels.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
Extravascular hemolysisEdit
Extravascular hemolysis refers to hemolysis taking place in the liver, spleen, bone marrow, and lymph nodes.<ref name="Stanley 2018" /> In this case little hemoglobin escapes into blood plasma.<ref name="Muller Jacobsen Healy McMickan 2006 pp. 229–241" /> The macrophages of the reticuloendothelial system in these organs engulf and destroy structurally-defective red blood cells, or those with antibodies attached, and release unconjugated bilirubin into the blood plasma circulation.<ref name="Rhodes Varacallo 2019">Template:Cite journal</ref><ref name=Sokol81>Template:Cite journal</ref> Typically, the spleen destroys mildly abnormal red blood cells or those coated with IgG-type antibodies,<ref name="BRAUNSTEIN.EVAN 2019">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref name="Hypersplenism 2019">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> while severely abnormal red blood cells or those coated with IgM-type antibodies are destroyed in the circulation or in the liver.<ref name="BRAUNSTEIN.EVAN 2019" />
If extravascular hemolysis is extensive, hemosiderin can be deposited in the spleen, bone marrow, kidney, liver, and other organs, resulting in hemosiderosis.<ref name="Muller Jacobsen Healy McMickan 2006 pp. 229–241"/>
Outside the bodyEdit
In vitro hemolysis can be caused by improper technique during collection of blood specimens, by the effects of mechanical processing of blood, or by bacterial action in cultured blood specimens.
From specimen collectionEdit
Most causes of in vitro hemolysis are related to specimen collection. Difficult collections, unsecure line connections, contamination, and incorrect needle size, as well as improper tube mixing and incorrectly filled tubes are all frequent causes of hemolysis.<ref>Template:Cite journal</ref>
In vitro hemolysis during specimen collection can cause inaccurate laboratory test results by contaminating the surrounding plasma with the contents of hemolyzed red blood cells. For example, the concentration of potassium inside red blood cells is much higher than in the plasma and so an elevated potassium level is usually found in biochemistry tests of hemolyzed blood.
After the blood collection process, in vitro hemolysis can still occur in a sample due to external factors, such as prolonged storage, incorrect storage conditions and excessive physical forces by dropping or vigorously mixing the tube.
Template:AnchorFrom mechanical blood processing during surgeryEdit
In some surgical procedures (especially some heart operations) where substantial blood loss is expected, machinery is used for intraoperative blood salvage. A centrifuge process takes blood from the patient, washes the red blood cells with normal saline, and returns them to the patient's blood circulation. Hemolysis may occur if the centrifuge rotates too quickly (generally greater than 500 rpm)—essentially this is hemolysis occurring outside of the body. Increased hemolysis occurs with massive amounts of sudden blood loss, because the process of returning a patient's cells must be done at a correspondingly higher speed to prevent hypotension, pH imbalance, and a number of other hemodynamic and blood level factors. Modeling of fluid flows to predict the likelihood of red cell membrane rupture in response to stress is an active area of research.<ref>Template:Cite journal</ref>
Template:AnchorFrom bacteria cultureEdit
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Visualizing the physical appearance of hemolysis in cultured blood samples may be used as a tool to determine the species of various Gram-positive bacteria infections (e.g., Streptococcus).
NomenclatureEdit
Hemolysis is sometimes called hematolysis, erythrolysis, or erythrocytolysis. The words hemolysis (Template:IPAc-en)<ref name="lpd"/> and hematolysis (Template:IPAc-en)<ref>Template:Cite Merriam-Webster</ref> both use combining forms conveying the idea of "lysis of blood" (hemo- or hemato- + -lysis). The words erythrolysis (Template:IPAc-en)<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> and erythrocytolysis (Template:IPAc-en)<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> both use combining forms conveying the idea of "lysis of erythrocytes" (erythro- ± cyto- + -lysis).
Red blood cells (erythrocytes) have a short lifespan (approximately 120 days), and old (senescent) cells are constantly removed and replaced with new ones via erythropoiesis. This breakdown/replacement process is called erythrocyte turnover. In this sense, erythrolysis or hemolysis is a normal process that happens continually. However, these terms are usually used to indicate that the lysis is pathological.
ComplicationsEdit
Pulmonary hypertension has been gaining recognition as a complication of chronic hereditary and acquired hemolysis.<ref name="Machado Gladwin 2010 pp. 30S–38S II">Template:Cite journal</ref><ref name="Rother Bell Hillmen Gladwin p=1653">Template:Cite journal</ref><ref name="Reiter Wang Tanus-Santos Hogg 2002 pp. 1383–1389 III">Template:Cite journal</ref> Free hemoglobin released during hemolysis inactivates the vasodilator nitric oxide (NO).<ref name="Machado Gladwin 2010 pp. 30S–38S II"/> Hemolysis also releases arginase that depletes L-arginine, the substrate needed for NO synthesis.<ref name="Machado Gladwin 2010 pp. 30S–38S II"/><ref name="Reiter Wang Tanus-Santos Hogg 2002 pp. 1383–1389 III"/> This reduces NO-dependent vasodilation<ref name="Machado Gladwin 2010 pp. 30S–38S II"/> and induces platelet activation, thrombin generation, procoagulant factors and tissue factor activation,<ref name="Machado Gladwin 2010 pp. 30S–38S II"/> contributing to the formation of thrombosis.<ref name="Machado Gladwin 2010 pp. 30S–38S II"/> This can lead to esophageal spasm and dysphagia, abdominal pain, erectile dysfunction, systemic hypertension, decreased organ perfusion, promotion of inflammation and coagulation, and thrombosis.<ref name="Rother Bell Hillmen Gladwin 2005 pp. 1653–1662 II">Template:Cite journal</ref>
Chronic hemolysis may also lead to endothelial dysfunction, heightened endothelin-1-mediated responses and vasculopathy.<ref name="Machado Gladwin 2010 pp. 30S–38S II"/><ref name="Schaer Buehler Alayash Belcher pp. 1276–1284 II">Template:Cite journal</ref> The release of heme leads to the production of bilirubin and depletion of plasma proteins, such as albumin, haptoglobin, and hemopexin, which may lead to jaundice.<ref name="Smith McCulloh p.">Template:Cite journal</ref><ref name="Schaer Vinchi Ingoglia Tolosano p.">Template:Cite journal File:CC-BY icon.svg Material was copied from this source, which is available under a Creative Commons License.</ref> It may also lead to increased levels of the heme breakdown product stercobilin in the stool.<ref name="BRAUNSTEIN.EVAN 2019" />
Splenectomy of those with hemolytic disorders appears to increase risk of developing pulmonary thrombosis.<ref name="Machado Gladwin 2010 pp. 30S–38S II"/>
Complications may also arise from the increased workload for the kidney as it secretes erythropoietin to stimulate the bone marrow to produce more reticulocytes (red blood cell precursors) to compensate for the loss of red blood cells due to hemolysis.<ref name="BRAUNSTEIN.EVAN 2019"/>